…returned in a Data Feed as object attributes.
Moved Data Feed parsing logic out of `Account.get_data()`. `DataSet` now takes care of much of the parsing directly as it creates its `DataPoint` elements.
Updated docs and tests for new features.
BACKWARDS INCOMPATIBLE:
Removed DataSet.dict property as this was broken for multiple metrics/dimensions (i.e. it only worked if there was *exactly* one dimension and one metric each).